Easy drive concrete fastener system

ABSTRACT

A depth-insensitive concrete fastener system is provided for securing roofing insulation materials to concrete roofing or decking. The concrete roofing or decking substructure is provided with a pre-drilled hole or bore having a predetermined diametrical extent. An anchor bolt fastener comprises a head portion, a pointed tip portion, and a shank portion interconnecting the head and tip portions. The shank portion has a first relatively smooth shank portion disposed adjacent to the head portion and extending toward the tip portion, and a second ribbed portion disposed adjacent to the tip portion and having an axial extent which is only a fractional portion of the entire axial extent of the fastener. The diametrical extent of the first smooth shank portion is less than that of the pre-drilled hole or bore defined within the concrete substructure, whereas the diametrical extent of the second ribbed shank portion is greater than the diametrical extent of the pre-drilled hole or bore defined within the concrete substructure. Therefore, when the anchor bolt fastener is impactly driven into the pre-drilled hole or bore of the concrete substructure, an interference or friction fit is defined between the anchor bolt fastener and interior sidewalls of the concrete substructure defining the pre-drilled hole or bore only along the axial extent of the second ribbed shank portion of the bolt fastener. Consequently, the fastener system is rendered depth-insensitive in that regardless of the depth to which the anchor bolt fastener is driven into the concrete substructure, the installation force does not increase beyond a predetermined limit. A roofing washer element may be pre-assembled upon the anchor bolt fastener as a result of being captured between the head and second ribbed shank portions of the bolt fastener.

This patent application is a Continuation patent application of priorpatent application Ser. No. 08/595,742 filed Feb. 2, 1996, now U.S. Pat.No. 5,661,938.

FIELD OF THE INVENTION

The present invention relates generally to fastener systems, and moreparticularly to a fastener system which is specifically adapted for usein connection with fastening or securing roofing membranes or insulationmaterials to concrete decking.

BACKGROUND OF THE INVENTION

Concrete anchor fastening systems for particular use in connection withconcrete substrate structures, such as, for example, those systems forsecuring or fastening roofing insulation materials to concrete decking,are of course well known. One such well known fastening system comprisesthe STRIKER™ concrete anchor fastening system which has been developedand marketed by ITW BUILDEX, 1349 West Bryn Mawr, Itasca, Ill. 60143, asubsidiary of the assignee of record of the present patent applicationembodying the present invention. The STRIKER™ concrete anchor fasteningsystem is disclosed within FIG. 1 and is generally indicated by thereference character 10. The STRIKER™ concrete anchor fastening system 10is adapted to secure or fasten roofing materials, such as, for example,sheets of rigid roofing insulation 12 to a concrete substrate orsubstructure 14, and is seen to comprise a STRIKER™ concrete anchor 16and a STRIKER™ plate 18 operatively associated therewith. The STRIKER™plate 18 may optionally be fabricated as either a metal plate or aplastic plate.

In accordance with the recommended installation techniques to beemployed in connection with the aforenoted prior art STRIKER™ concreteanchor fastening system 10, a standard or conventional rotary hammerdrill is first used to drill a pilot hole through the insulation 12 andinto the concrete substructure 14, the pilot hole having an axial depthwhich is at least one-quarter inch (1/4") deeper than the finalengagement depth of the concrete anchor 16 so as to accommodate, forexample, debris from the drilling operation. STRIKER™ plate 18, alongwith the STRIKER™ concrete anchor 16 which may be pre-assembledtherewith by insertion through a central aperture 20 thereof, is thenpositioned atop the rigid insulation 12 such that the concrete anchor 16can be inserted into the drilled pilot hole. The STRIKER™ concreteanchor 16 can then be fully inserted through the rigid insulation 12 andinto the concrete substructure 14 by means of a suitable hammer or othertype of impact tool.

As can be seen from further reference to FIG. 1, the STRIKER™ concreteanchor 16 is of the type comprising a pointed tip portion 22, a headportion 24, and a body or shank portion 26. The body or shank portion 26is provided with a circumferentially arranged series of substantiallyaxially extending, alternating ribs and grooves 28, the ribs and grooves28 preferably having a slight spiral or twisted orientation with respectto the longitudinal axis of the anchor 16. The outer diametrical extentof the ribs is greater than the corresponding diametrical extent of thepilot hole drilled within the rigid insulation 12 and concretesubstructure 14 such that when the concrete anchor 16 is hammered intothe concrete substrate or decking 14, a good interference fit is definedbetween the concrete anchor 16 and the annular surrounding wall surfacesof the concrete substructure defining the pilot hole drilled therein.This interference fit defined between the concrete anchor 16 and thesurrounding walls of the pilot hole drilled within the concrete decking14 serves to determine the retaining force or pull-out resistancecharacteristic of the concrete anchor 16. The retaining force orpull-out resistance characteristic of the concrete anchor 16 should ofcourse be sufficient to prevent the concrete anchor 16 from becomingdislodged from the concrete decking 14 even, for example, s,under highwind conditions, which create large uplift force so as to in factmaintain the rigid insulation 12 affixed to the concrete decking 14.

While the aforenoted prior art STRIKER™ concrete anchor fastening system10 has been extremely commercially successful, it has been realized thatin view of the fact that the series of ribs and grooves 28 extendaxially throughout substantially the entire axial length of the concreteanchor 16, that is, along substantially the entire axial length of theshank portion 26 defined between the tip portion 22 and the head portion24, the STRIKER™ concrete anchor 16 is of the type which ischaracterized as depth-sensitive A depth-sensitive fastener exhibitsdriving characteristics wherein the driving or impact force required toinstall the anchor 16 within the pilot hole of the concrete decking 14and rigid insulation 12 is directly proportional to the depth ofembedment of the installed fastener, or in other words, the deeper thefastener is driven into the drilled pilot hole, the more difficult it isto install the STRIKER™ concrete anchor 16 because of theever-increasing axial length of the plurality of ribs that encounter thesidewall portions of the concrete decking 14, defining the driller pilothole and which define the aforenoted interference or friction fit withthe ribs of anchor 16, as the anchor 16 is progressively axiallyinserted into the pilot hole.

In an effort to overcome the aforenoted installation difficultiesattendant the prior art STRIKER™ anchor 16, depth-insensitive anchorshave been developed. One such anchor is disclosed in U.S. Pat. No.5,035,559 which issued to Martin J. Nilsen on Jul. 30, 1991 and isassigned to the assignee of record of this patent application. Thisparticular type of anchor, however, is substantially different from theSTRIKER™ anchor 16 in that in lieu of defining an interference orfriction fit between the STRIKER™ anchor and the sidewalls of theconcrete deck defining the drilled pilot hole as in the case of thesystem disclosed in FIG. 1, the concrete anchor disclosed in U.S. Pat.No. 5,035,559 is of the compression fit type in that the shank of theanchor of such patent undergoes bending and straightening deformationsas the shank portions of the anchor, offset with respect to each otherand with respect to the longitudinal axis of the anchor, encounter thesidewall portions 52 of the hole 50 defined within the body of concrete54.

Another anchor for use within concrete or masonry, and of theinterterference-fit type, is disclosed in U.S. Pat. No. 4,350,464 whichissued to Richard L. Brothers on Sep. 21, 1982. This anchor, however, isnot truly of the depth-insensitive type in view of the fact that thediameter of the shaft 13 of the anchor 10 has a diametrical extent whichis substantially or essentially the same as that of the hole 101 formedwithin the concrete 100. In addition, the anchor of this patent is quitedifficult and costly to manufacture in view of the need for the anchorshank portion to undergo bead line welding in order to provide theanchor 10 with the patterned weld bead lines 14.

A need therefore exists within the concrete fastener system art for anew and improved depth-insensitive concrete fastener system whichemploys a depth-insensitive concrete anchor of the interference orfriction-fit type.

OBJECTS OF THE INVENTION

Accordingly, it is an object of the present invention to provide a newand improved depth-insensitive concrete fastener system.

Another object of the present invention is to provide a new and improveddepth-insensitive concrete fastener system wherein the system comprisesor incorporates therein a depth-insensitive concrete anchor device ofthe interference or friction-fit type.

Still another object of the present invention is to provide a new andimproved depth-insensitive concrete fastener system wherein the systemcan be effectively utilized in connection with the fastening or securingof rigid insulation panels and membranes to concrete substrates whichare preferably concrete decks.

Yet another object of the present invention is to provide a new andimproved depth-insensitive concrete fastener system within which adepth-insensitive concrete anchor enables relatively easy installationwithin a concrete substrate or substructure and yet exhibitssufficiently great pull-out resistance so as to reliably retain rigidroofing insulation panels and membranes, for example, to concrete roofdecking substrates or substructures.

A further object of the present invention is to provide a new andimproved depth-insensitive concrete fastener system which incorporatestherein the use of a concrete anchor which establishes an interferenceor friction-type fit, with the sidewalls of a concrete substrate orsubstructure defining a hole or bore within which the anchor isdrivingly inserted, wherein the interference or friction fit only actsalong a predetermined axial length of the anchor such that the anchor iseffectively rendered depth-insensitive regardless of the depth to whichthe anchor is driven into the hole or bore defined within the concretesubstrate or substructure.

A still further object of the present invention is to provide a new andimproved depth-insensitive concrete fastener system which incorporatestherewithin a concrete anchor which is relatively simple and inexpensiveto manufacture.

SUMMARY OF THE INVENTION

The foregoing and other objects of the present invention are achievedthrough the provision of a new and improved depth-insensitive concretefastener system which incorporates therein a depth-insensitive anchorbolt device. The anchor bolt device comprises a pointed tip portion, ahead portion, and a shank portion extending axially between the pointedtip and head portions of the bolt fastener. The anchor bolt device isadapted to be impactly driven into a pre-drilled hole or bore providedwithin a concrete substrate or substructure, such as, for example,concrete decking, so as to fasten, for example, rigid roofing insulationmaterials to the concrete decking. The hole or bore pre-drilled into theconcrete decking has a predetermined diametrical extent, and inaccordance with the present invention fastener system, thedepth-insensitive anchor bolt device has a first, relatively smoothshank portion, commencing immediately adjacent to the head portion ofthe bolt fastener and extending toward the pointed tip portion of thebolt fastener, which has a diametrical extent which is slightly lessthan that of the pre-drilled hole or bore defined within the concretedecking. In addition, a second shank portion, commencing at thetermination of the first shank portion and terminating at the pointedtip portion of the bolt fastener, comprises a circumferential array ofsubstantially axially extending ribs and alternating grooves which areintegrally formed with and upon the shank portion of the bolt fastener.The outer diametrical extent of the second ribbed shank portion of thebolt fastener is greater than the predetermined diametrical extent ofthe hole or bore pre-drilled within the concrete decking and is alsogreater than the predetermined diametrical extent of the first shankportion of the bolt fastener. The axial extent of the second ribbedshank portion of the bolt fastener is substantially less than thecorresponding axial length of the anchor bolt fastener and preferablyhas an axial extent which is only a fractional portion of the axialextent of the anchor bolt fastener.

In view of the foregoing, an interference or friction fit is onlydeveloped between the anchor bolt fastener and the sidewalls of theconcrete decking defining the pre-drilled hole or bore along the axialextent of the second ribbed shank portion of the anchor bolt fastener.The specific length of the second ribbed shank portion of the anchorbolt fastener can of course be selectively varied in order toselectively or optimally control, limit, or minimize the installationforce required to drivingly install the anchor bolt fastener within thepre-drilled hole or bore formed within the concrete decking whileconcomitantly selectively or optimally determining the pull-outresistance characteristics of the anchor bolt fastener. In lieu of theribs of the second shank portion of the bolt fastener being trulyaxially oriented with respect to the longitudinal axis of the anchorbolt fastener, the ribs may be slightly skewed, twisted, sprialled, orotherwise similarly oriented with respect to the longitudinal axis ofthe bolt fastener, the primary requisite of the ribbed structure beingthe fact that the ribs are substantially axially oriented.

In accordance with a further feature of the present invention, theanchor bolt fastener may be pre-assembled with the striker or washerplate wherein the striker or washer plate is effectively retained uponthe bolt fastener by being captured between the head portion of the boltfastener and the circumferential array of ribs comprising the secondribbed shank portion of the bolt fastener.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features, and attendant advantages of the presentinvention will be more fully appreciated from the following detaileddescription when considered in connection with the accompanying drawingsin which like reference characters designate like or corresponding partsthroughout the several views, and wherein:

FIG. 1 is a perspective view of a PRIOR ART depth-sensitive concretefastener system utilized for attaching roofing insulation materialsunderlying concrete decking substructures;

FIG. 2 a schematic view of the depth-insensitive concrete fastenersystem constructed in accordance with the principles of the presentinvention whereby roofing insulation materials may be secured orfastened to underlying concrete decking substructures, the roofinginsulation material having been omitted from this view for the purposesof clarity;

FIG. 3 is a side elevational view of a depth-insensitive anchor boltfastener constructed in accordance with the principles of the presentinvention and incorporated within the depthinsensitive concrete fastenersystem of the present invention;

FIG. 4 is a cross-sectional view of the depth-insensitive anchor boltfastener of FIG. 3 as taken along the lines 4--4 of FIG. 3;

FIG. 5 is a perspective view of the depth-insensitive anchor boltfastener shown in FIGS. 2-4 prior to assembly with a roofing washer orstress plate for use within the depth-insensitive concrete fastenersystem of FIG. 2.

FIG. 6 is a view similar to that of FIG. 4 showing, however, a fastenershank portion wherein the ribbed portions thereof have substantiallytriangular cross-sectional configuration; and

FIG. 7 is a view similar to that of FIG. 4 showing, however, a fastenershank portion wherein the ribbed portions thereof have a substantiallysquare-shaped cross-sectional configuration.

DETAILED DESCRIPTION OF THE INVENTION:

Referring now to the drawings, and more particularly to FIG. 2 thereof,the new and improved depth-insensitive concrete fastener system,constructed in accordance with the principles of the present invention,is illustrated and generally indicated by the reference character 110.It is to be appreciated that the new and improved fastener system 110 ofthe present invention comprises a fastening system which is similar tothat system 10 disclosed within FIG. 1 so as to secure or fasten, forexample, a sheet of rigid roofing insulation material 112 to a concretesubstrate or substructure, such as, for example, concrete decking 114.While the roofing insulation material has been shown schematically inthe system of FIG. 2 simply for clarity purposes, it is to be understoodthat the sheet of insulation material is to be secured or fastened atopthe concrete decking 114 in a manner similar to the disposition of theinsulation material 12 with respect to the concrete decking 14 of thesystem 10 of FIG. 1, and in addition, a suitable roofing washer orwasher plate, also shown schematically at 118 and, similar, for example,to the washer plate 18 of the system of FIG. 1, is preferably disposedatop the roofing insulation material. While a washer plate similar tothe washer plate 18 of the system of FIG. 1, that is, wherein the plateis fabricated from metal and has a substantially square configuration,may be utilized within the system 110 of the present invention, otherwasher plates or roofing washers may be alternatively employed. One suchtype of alternative roofing washer or washer plate is disclosed withinFIG. 5 at 118 and is seen to have a substantially circularconfiguration. This washer plate 118 is also fabricated from a suitableplastic material which is substantially rigid yet somewhat pliable orflexible, and is provided with a central aperture 120 through which adepth-insensitive anchor bolt device 116, characteristic of the presentinvention system, may pass so as to be drivingly inserted through theslab of roofing insulation material 112 and into the concrete decking114.

With additional reference now also being made to FIGS. 3 and 4, it isseen that the depth-insensitive anchor bolt device 116 of the presentinvention system 110 is similar to the depth-sensitive anchor boltdevice 16 of the PRIOR ART system 10 of FIG. 1 in that the anchor bolt116 of the present invention comprises a pointed tip portion 122, a headportion 124, and a shank portion 126 extending between the pointed tipportion 122 and the head portion 124. Unlike the depth-sensitive anchorbolt device 16 of the PRIOR ART system 10 of FIG. 1, however, whereinthe shank portion 26 of the anchor bolt device 16 is provided with itscircumferentially arranged series of alternating ribs and grooves 28which extend axially throughout substantially the entire axial length ofthe shank portion 26 of the anchor bolt device 16, the shank portion 126of the anchor bolt device 116 of the present invention is seen tocomprise a first, relatively smooth shank portion 132 which commencesimmediately adjacent to the head portion 124 and extends axially towardthe pointed tip portion 122. In addition, a second shank portion,commencing at the termination of the first shank portion 132 andterminating at the pointed tip portion 122, comprises a circumferentialarray of substantially axially extending ribs 128 and alternatinggrooves 130, the ribs 128 and grooves 130 being integrally formedupon,and from the material comprising, the bolt device 116.

It is further appreciated that the relatively smooth, first shankportion 132 of the anchor bolt 116 has an external diametrical extent ordimension D₁, as noted in FIGS. 2 and 3, whereas the externaldiametrical extent or dimension of the second shank portion of theanchor bolt 116, as taken through or along a diametrical plane extendingthrough the substantially axially extending ribs 128, has apredetermined value D₂ which is substantially greater than thediametrical extent or dimension D₁, as noted in FIG. 3 and 4.Consequently, when the depth-insensitive anchor bolt device 116 is to bedrivingly impacted or similarly inserted into a concrete substrate orsubstructure 114, comprising, for example, concrete decking, so as tosecure roofing insulation material 112 thereto, the concrete decking 114is initially provided with a pre-drilled hole or bore 134 which has adiametrical extent or dimensional value D₃ which is slightly greaterthan the diametrical extent D₁ of the first, relatively smooth shankportion 132 of the anchor bolt device 116 but somewhat less than theexternal diametrical extent D₂ of the second ribbed shank portion 128 ofthe anchor bolt device 116. As a result of such interrelated structurescomprising the bore or hole 134 of the concrete substrate 114, and thefirst and second shank portions 132 and 128 of the anchor bolt device116, and appreciating the relative diametrical extents or dimensions ofsuch structures, as the anchor bolt device 116 is driven into the holeor bore 134 of the concrete decking 114, an interference or friction fitis defined between the interior sidewall portions 136, of the concretedecking 114 defining the hole or bore 134, and the anchor bolt device116 only along the axial extent of the second ribbed shank portion 128.This definition or development of the inference or friction fit onlyalong or throughout the axial extent of the second ribbed shank portion128 of the anchor bolt device 116 is precisely the feature which rendersthe present invention fastener system 110 depth-insensitive.

More particularly, as can be seen and appreciated from FIG. 2, 3, and 5,the axial extent of the second ribbed shank portion 128 of the boltfastener 116 is substantially less than the axial extent of the entireshank portion 126 of the bolt fastener 116, and preferably, the axialextent of the second ribbed shank portion 128 comprises only afractional portion of the axial extent of the entire shank portion 126.More specifically, such fractional portion may be, for example,approximately one-sixth the length of the entire shank portion 126 ofthe bolt fastener 116. In addition, the axial extent of the secondribbed shank portion 128 must comprise only a fractional portion of theaxial extent or depth of the pre-drilled hole or bore 134. Consequently,once the anchor bolt member 116 is drivingly impacted and inserted intothe pre-drilled bore or hole 134 of the concrete decking 114 such thatthe second ribbed shank portion 128 of the anchor bolt member 116 isentirely enveloped by the surrounding sidewalls 136 of the decking 114defining hole or bore 134, further axial insertion penetration of thebolt member 116 into the hole or bore 134 does not further increasedriving or insertion resistance forces or the required force ofinstallation. Such force of installation, or the driving or insertionresistance force, is limited by or is a function of the axial extent ofthe second ribbed shank portion 128 of the bolt member 116, andtherefore, the anchor bolt member 116, and the fastener system 110incorporating such bolt member 116, is effectively depth-insensitive.This is seen to be in marked contrast to the depth-sensitivecharacteristics of the bolt member 16 and the system 10 of the PRIOR ARTas illustrated in FIG. 1. In accordance with the system of FIG. 1, asthe bolt member 16 is progressively inserted or driven into the concretedecking 14, a correspondingly progressively increasing volume of theribbed shank portion 28 of the anchor bolt 16 establishes aprogressively increasing interference or friction fit with thepre-drilled hole or bore defined within the concrete substrate 14whereby the required or encountered force of installation iscorrespondingly increased thereby rendering the installation harder andharder as the submerged depth of the anchor bolt 16 within the decking14 increases.

In accordance then with the system 110 of the present invention, therequired insertion or installation force is limited or maxed-out oncethe second ribbed shank portion 128 of the anchor bolt 116 is entirelyinserted or submerged within the hole or bore 134 of the concretedecking 114, and this limitation of the insertion or installation forcecan be optimally or selectively controlled, minimized, or the like, byselectively varying or predetermining the axial extent of the secondribbed shank portion 128 as defined upon a particular or specific anchorbolt fastener 116 depending upon particular jobsite operationalparameters or requirements The axial extent of the second ribbed shankportion 128 of the bolt fastener 116 also, of course, determines thepull-out resistance characteristics which the fastener 116 will exhibitunder operational conditions. Therefore, depending upon the particularparameters, environment, or requirements of a particular jobsite,fastening operation, or the like, the specific or predetermined lengthof the second ribbed shank portion 128 of the anchor bolt member 116 canbe selectively varied in order to selectively or optimally control,limit, or minimize the installation force required to drivingly installthe anchor bolt fastener within the pre-drilled hole or bore formedwithin the concrete decking while concomitantly selectively or optimallydetermining the pull-out resistance characteristics of the concreteanchor fastener. In other words, a predeterminedly balanced system canbe selected or developed with respect to the desired or requiredinstallation forces versus pull-out resistance values by properlychoosing an appropriate axial extent value for the second ribbed shankportion 128 upon the concrete anchor member 116.

While it has been noted that the ribs 128 of the shank portion 126 ofthe concrete anchor member 116 can be axially aligned with respect tothe longitudinal axis L of the concrete anchor member 116, it ispreferred that the ribs 128 actually be angularly offset with respect tothe longitudinal axis L by means of a predetermined angle A. This angleA can vary between, for example, 0° and 45°, with an angle of 5° ofbeing preferred, the angle A being illustrated in FIG. 3. If the angle Ais greater than 45°, it will be quite difficult to drive the anchor 116into the concrete substrate. Alternatively, the ribs 128 may have aslightly twisted or spiralled orientation with respect to thelongitudinal axis L of the concrete anchor fastener 116. It is furthernoted that as clearly seen from the cross-sectional view of FIG. 4, thecross-sectional configuration of each rib member 128 of the concreteanchor fastener 116 comprises a rounded lobe, however, alternativeconfigurations are possible, such as, for example, wherein each ribmember 128 may have a substantially square or triangular cross-sectionalconfiguration as respectively illustrated at 228 and 328, along withalternating grooves 230 and 330, in FIGS. 6 and 7. However, the roundedconfiguration is preferred in view of the fact that each rib member 128would then present a greater surface area of engagement with respect tothe internal peripheral wall surfaces 136 of the hole or bore 134. Inaddition, such rounded surfaces tend to compress the concrete sidewalls136 as opposed to scraping or cutting the same, resulting in greaterpull-out resistance values. The angular orientation of the ribs 128 withrespect to the longitudinal axis L also increases the pull-outresistance of the anchor with respect to an anchor wherein the ribs 128are aligned with the longitudinal axis L. Still further, while theanchor has been illustrated with eight (8) ribs 128 disposed about theperiphery thereof as seen in FIG. 4, the number of ribs can vary. Forexample, the number of ribs 128 may be six (6) or seven (7), and whileit has been observed that such variation in the number of ribs 128 hassubstantially no effect upon the insertion force required to install theanchor 116 within the concrete substrate or substructure, the pull-outresistance will vary with test results indicating the largest pull-outresistance being achieved when seven (7) ribs 128 were employed.

As a last feature characteristic of the present invention and withreference being made again to FIG. 5, it is desirable to provide theanchor fastener 116 and the roofing washer or plate 118 as a two-piecepre-assembled component. In particular, a central undersurface portion138 of the roofing washer 118 has a frustoconical configuration and isintegrally formed with the washer 118 so as to depend downwardlytherefrom. The distal end of the portion 138 is provided with anaperture, not shown, through which the anchor fastener 116 passes, andthe internal diameter of such aperture is slightly larger than thediametrical extent D₁ of the first smooth shank portion 132 of thefastener 116, and substantially corresponds to the diametrical extent ofthe aperture 120 formed within the substantially planar roofing washer118. In this manner, the anchor fastener 116 can be axially moved withrespect to the washer plate 118 without any difficulty whatever.However, the diametrical extent D₂ of the second ribbed shank portion128 of the fastener 116, as well as the diametrical extent of the headportion 124 of the fastener 116, are substantially greater than theexternal diametrical extent D₁ of the first smooth shank portion 132 ofthe fastener 116 as well as the internal diameter of the aperture 120and the aperture, not shown, formed within the frustoconical portion 138of the washer 118. Consequently, the washer plate 118 is effectivelycaptured upon the anchor fastener 116 as a result of the outerdiametrical or peripheral portion of the head portion 124 of thefastener 116 encountering the annular wall portion of washer plate 118surrounding aperture 120, and the upper axial end portions of the ribs128 of the fastener 116 encountering the distal annular wall portion offrustoconical portion 138 of washer plate 118, during extreme axialpositional movements of the washer plate 118 and the anchor fastener 116with respect to each other. The pre-assembled component comprising theanchor fastener 116 and the washer plate 118 enables workmen to readilyuse such structures or components at the jobsite, as when installationof the anchor fasteners 116 into the concrete decking 114 is to beperformed, without initially requiring assembly of the fasteners 116 andthe roofing washers 118.

Thus, it may be seen that the present invention has provided a new andimproved depth-insensitive concrete fastener system which is especiallyadapted for use in connection with the securement or fastening ofroofing insulation or membrane materials to concrete roofing decking. Inparticular, the new and improved depth-insensitive concrete fastenersystem incorporates therein an anchor device or member which establishesan interference or friction fit with interior sidewall portions of ahole or bore pre-drilled within the concrete roofing decking only alonga predetermined limited axial extent of the anchor device or fastenersuch that the anchor fastener is effectively rendered depth-insensitivewith respect to the concrete roofing decking whereby, in turn, theentire concrete fastener system exhibits depth-insensitivecharacteristics. As a result of such depth-insensitivity, theinstallation force required to impactly drive the anchor fastener intothe pre-drilled hole or bore of the concrete decking to its fullestextent has a maximum or limited value which does not increase further asthe anchor fastener is driven further bore of t pre-drilled hole or boreof the concrete decking. Concomitantly, the pull-out resistancecharacteristics of the fastening system are likewise determined by theaxial extent of the interference or friction fit defined between theanchor fastener and the interior sidewall portions of the hole or boredefined within the concrete decking, and even though the installationforce is limited, the pull-out resistance values or characteristics aremore than adequate or sufficient so as to reliably retain the roofinginsulation or membrane materials in their secured or fastened state withrespect tot eh underlying concrete decking.

It is obviously noted that various modifications and variations may beimparted to the depth-insensitive concrete fastener system of thepresent invention, in accordance with the above teachings, withoutdeparting from the basic principles of the invention, It is therefore tobe understood that within the scope of the appended claims, the presentinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be protected by Letters Patent,is:
 1. A depth-insensitive concrete fastener system for fasteningmaterial objects to a concrete substructure, comprising:a concretesubstructure; a bore-hole, having a predetermined diametrical extent,defined within said concrete substructure; a material object disposedupon said concrete substructure; and anchor fastener means, comprising atip portion, a head portion, and a shank portion, interconnecting saidtip and head portions, for insertion within said bore-hole of saidconcrete substructure for securing said material object upon saidconcrete substructure; said shank portion of said anchor fastener meansbeing solid, formed from a material and as a structural component whichis substantially non-deformable when driven into said bore-hole definedwithin said concrete substructure, and comprising a first portioncommencing immediately adjacent to said head portion, extending axiallytoward said tip portion, and having a first predetermined diametricalextent which is less than said predetermined diametrical extent of saidbore-hole defined within said concrete substructure; and a second ribbedportion interposed between said first shank portion and said tip portionand comprising a circumferential array of substantially axiallyextending rib means, which are integrally formed upon, and from saidmaterial comprising, said shank portion of said anchor fastener means,which have a second predetermined diametrical extent which is greaterthan said predetermined diametrical extent of said bore-hole definedwithin said concrete substructure, which have an axial extent which isonly a fractional portion of the axial extent of said shank portion ofsaid anchor fastener means, and which have a substantially uniformcross-sectional configuration throughout said axial extent thereof, forpermitting axial insertion of said anchor fastener means within saidbore-hole defined within said concrete substructure in a substantiallylinear, impact driven manner and with an interference fit definedbetween said substantially axially extending, uniformly cross-sectionedrib means of said anchor fastener means and said bore-hole definedwithin said concrete substructure only along said axial extent of saidsecond ribbed portion of said anchor fastener means so as to render saidanchor fastener means, and said concrete fastener system,depth-insensitive regardless of the depth to which said anchor fastenermeans is driven into said bore-hole defined within said concretesubstructure.
 2. The depth-insensitive concrete fastener system as setforth in claim 1, wherein:said bore-hole has a predetermined axialdepth; and said axial extent of said second ribbed portion of said shankportion of said anchor fastener means is only a fractional portion ofsaid axial depth of said bore-hole defined within said concretesubstructure.
 3. The system as set forth in claim 1, wherein:said tipportion of said anchor fastener means comprises a substantially pointedtip.
 4. The system as set forth in claim 1, wherein:said shank portionof said anchor fastener means comprises a longitudinal axis; and saidsubstantially axially extending ribs are offset with respect to saidlongitudinal axis of said shank portion of said anchor fastener means bymeans of an angle of approximately five degrees (5°).
 5. The system asset forth in claim 1, wherein:each one of said plurality of ribs of saidribbed portion of said shank portion of said anchor fastener means has asubstantially rounded-lobe cross-sectional configuration.
 6. Adepth-insensitive concrete fastener system for fastening roofingmaterials to a concrete roofing deck, comprising:a concrete roofingdeck; a bore-hole, having a predetermined diametrical extent, definedwithin said concrete roofing deck; roofing material disposed upon saidconcrete roofing deck so as to be fastened thereto; and anchor fastenermeans, comprising a tip portion, a head portion, and a shank portion,interconnecting said tip and head portions, for insertion through saidroofing material and into said bore-hole defined within said concreteroofing deck for fastening said roofing material upon said concreteroofing deck; said shank portion of said anchor fastener means beingsolid, formed from a material and as a structural component which issubstantially non-deformable when driven into said bore-hole definedwithin said concrete roofing deck, and comprising a first portioncommencing immediately adjacent to said head portion, extending axiallytoward said tip portion, and having a first predetermined diametricalextent which is less than said predetermined diametrical extent of saidbore-hole defined within said concrete roofing deck; and a second ribbedportion interposed between said first shank portion and said tip portionand comprising a circumferential array of substantially axiallyextending rib means, which are integrally formed upon, and from saidmaterial comprising, said shank portion of said anchor fastener means,which have a second predetermined diametrical extent which is greaterthan said predetermined diametrical extent of said bore-hole definedwithin said concrete roofing deck, which have an axial extent which isonly a fractional portion of the axial extent of said shank portion ofsaid anchor fastener means, and which have a substantially uniformrounded lobe cross-sectional configuration throughout said axial extentthereof, for permitting axial insertion of said anchor fastener meanswithin said bore-hole defined within said concrete roofing deck in asubstantially linear, impact driven manner and with an interference fitdefined between said substantially axially extending, uniformlygeometrical cross-sectioned rib means of said anchor fastener means andsaid bore-hole defined within said concrete roofing deck only along saidaxial extent of said second ribbed portion of said anchor fastener meansso as to render said anchor fastener means, and said concrete fastenersystem, depth-insensitive regardless of the depth to which said anchorfastener means is drivingly inserted into said bore-hole defined withinsaid concrete roofing deck.
 7. The system as set forth in claim 6,wherein:said bore-hole has a predetermined axial depth; and said axialextent of said second ribbed portion of said shank portion of saidanchor fastener means is only a fractional portion of said axial depthof said bore-hole defined within said concrete roofing deck.
 8. Thesystem as set forth in claim 6, wherein:said tip portion of said anchorfastener means comprises a substantially pointed tip.
 9. The system asset forth in claim 6, wherein:said shank portion of said anchor fastenermeans comprises a longitudinal axis; and said substantially axiallyextending ribs are offset with respect to said longitudinal axis of saidshank portion of said anchor fastener means by means of an angle ofapproximately five degrees (5°).
 10. A system as set forth in claim 6,wherein:said roofing material comprises a sheet of roofing insulation.11. A depth-insensitive concrete fastener system for fastening roofingmaterial to a concrete roofing deck, comprising:a concrete roofing deck;a bore-hole, having predetermined diametrical extent, defined saidconcrete roofing deck; roofing material disposed upon said concreteroofing deck so as to be fastened thereto; a washer plate disposed uponsaid roofing material; and anchor fastener means, comprising a tipportion, a head portion, and a shank portion, interconnecting said tipand head portions, for insertion through said washer plate and saidroofing material and into said bore-hole defined within said concreteroofing deck for fastening said roofing material upon said concreteroofing deck; said shank portion of said anchor fastener means beingsolid, formed from a material and as a structural component which issubstantially non-deformable when driven into said bore-hole definedwithin said concrete roofing deck, and comprising a first portioncommencing immediately adjacent to said head portion, extending axiallytoward said tip portion, and having a first predetermined diametricalextent which is less than said predetermined diametrical extent of saidbore-hole defined within said concrete roofing deck; and a second ribbedportion interposed between said first shank portion and said tip portionand comprising a circumferential array of substantially axiallyextending rib means, which are integrally formed upon, and from saidmaterial comprising, said shank portion of said anchor fastener means,which have a second predetermined diametrical extent which is greaterthan said predetermined diametrical extent of said bore-hole definedwithin said concrete roofing deck, which have an axial extent which isonly a fractional portion of the axial extent of said shank portion ofsaid anchor fastener means, and which have a substantially uniformgeometrical cross-sectional configuration throughout said axial extentthereof, for permitting axial insertion of said anchor fastener meanswithin said bore-hole defined within said concrete roofing deck in asubstantially linear, impact driven manner and with an interference fitdefined between said substantially axially extending, uniformlygeometrical cross-sectioned rib means of said anchor fastener means andsaid bore-hole defined within said concrete roofing deck only along saidaxial extent of said second ribbed portion of said anchor fastener meansso as to render said anchor fastener means, and said concrete fastenersystem, depth-insensitive regardless of the depth to which said anchorfastener means is drivingly inserted into said bore-hole defined withinsaid concrete roofing deck.
 12. The system as set forth in claim 11,wherein:each one of said plurality of ribs of said ribbed portion ofsaid shank portion of said anchor fastener means has a substantiallysquare-shaped cross-sectional configuration.
 13. The system as set forthin claim 11 wherein:said bore-hole has a predetermined axial depth; andsaid axial extent of said second ribbed portion of said shank portion ofsaid anchor fastener means is only a fractional portion of said axialdepth of said bore-hole defined within said concrete roofing deck. 14.The system as set forth in claim 11, wherein:said tip portion of saidanchor fastener means comprises a substantially pointed tip.
 15. Thesystem as set forth in claim 11, wherein:said shank portion of saidanchor fastener means comprises a longitudinal axis; and saidsubstantially axially extending ribs are offset with respect to saidlongitudinal axis of said shank portion of said anchor fastener means bymeans of an angle of approximately five degrees (5°).
 16. The system asset forth in claim 11, wherein:each one of said plurality of ribs ofsaid ribbed portion of said shank portion of said anchor fastener meanshas a substantially rounded-lobe cross-sectional configuration.
 17. Thesystem as set forth in claim 11, wherein:said roofing material comprisesa sheet of roofing insulation.
 18. The system as set forth in claim 11,wherein:said washer plate and said anchor fastener means comprise apre-assembled component.
 19. The system as set forth in claim 18,wherein:said washer plate has an aperture defined therethrough having adiametrical extent which is greater than said first predetermineddiametrical extent of said first portion of said shank portion of saidanchor fastener means, but which is less than the diametrical extent ofsaid head portion of said anchor fastener means, and is also less thansaid second predetermined diametrical extent of said second ribbedportion of said shank portion of said anchor fastener means, such thatwhile said washer plate may freely move axially with respect to saidanchor fastener means and along said first portion of said shank portionof said anchor fastener means, said washer plate is captured upon saidfirst portion of said shank, portion of said anchor fastener meansbetween said head portion of said anchor fastener means and said secondribbed portion of said shank portion of said anchor fastener means. 20.The system as set forth in claim 11, wherein:said washer plate isfabricated from metal and has a substantially square configuration. 21.The system as set forth in claim 11, wherein:said washer plate isfabricated from a plastic material and has a substantially circularconfiguration.
 22. The system as set forth in claim 11, wherein:each oneof said plurality of ribs of said ribbed portion of said shank portionof said anchor fastener means has a substantially triangularcross-sectional configuration.